Addex: ADX71943 Demonstrates Analgesic Effects in Pain Models

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Geneva, Switzerland, 8 February 2010 - Addex Pharmaceuticals (SIX:ADXN), the
allosteric modulation company, announced today that ADX71943 has demonstrated
statistically significant analgesic-like effects in three preclinical models of
pain.

In the first model, ADX71943 reversed complete Freund adjuvant (CFA)-induced
reductions in withdrawal thresholds in a dose-related manner, with a minimum
statistically significant effective oral dose of 10 mg/kg. In a second model
(Formalin test), ADX71943 showed anti-nociceptive effect after oral
administration of 3 to 10 mg/kg. In a third model, an increased visceral pain
threshold was seen using ADX71943 with a minimum statistically significant
effective dose between 3 and 10 mg/kg.

ADX71943 is an orally available positive allosteric modulator (PAM) of the
GABA(B) receptor that has potential for treatment of osteoarthritis pain and
chronic nociceptive pain as well as other indications. ADX71943 has a good
developability profile and is expected to enter clinical testing in the fourth
quarter 2010.

"We are impressed with the profile of the compound and by its activity in these
models. Furthermore,
minimum effective doses observed in the preclinical models and the
pharmacokinetic properties of the compound support prediction of treatment
regimens in humans compatible with the target patient population and disease"
said Sonia Poli, head of non-clinical development at Addex.

GABA(B) activation is a clinically validated mechanism. Baclofen, a GABA(B)
agonist, is widely used for its muscle relaxant properties in the control of
spasticity caused by multiple sclerosis, cerebral palsy or certain injuries to
the spine. Furthermore, Baclofen is a powerful analgesic agent, especially when
delivered intrathecally. However, rapid induction of tolerance and dose limiting
CNS-mediated side effects (e.g. sedation, hypothermia, memory impairment)
prevent baclofen from being widely prescribed for pain relief despite its
analgesic properties. ADX71943, an allosteric modulator with a differentiated
profile, could avoid the tolerance and dose limiting side effects commonly
associated with baclofen.

Osteoarthritis (OA) is a widespread condition affecting the elderly population
in particular. One of the most debilitating symptoms is chronic pain associated
with OA. Patients suffering from chronic pain will require treatment over the
long-term. There is a clear need for drugs with better side effect profiles than
current marketed drugs (e.g. non-steroidal anti-inflammatory drugs and opioids).

Addex Pharmaceuticals (www.addexpharma.com )
utilizes its unique proprietary platform technologies to discover and develop
allosteric modulators for human health. Allosteric modulators are a different
kind of orally available small molecule therapeutic agent, which we believe will
offer a competitive advantage over classical drugs. With 15 programs in
development, the Addex pipeline demonstrates the productivity and broad
potential of our unparalleled platform technologies. The most advanced product,
ADX48621, an mGluR5 negative allosteric modulator (NAM), has completed Phase I
testing and is scheduled to start Phase II testing for Parkinson's disease
levodopa associated dyskinesia (PD-LID) later in 2010.
Our products and technology already have proven their value through our
relationships with four of the top 10 pharmaceutical companies in the world.
Specifically, under an agreement withOrtho-McNeil-Janssen Inc., a Johnson &
Johnson company, ADX71149, an mGluR2 positive allosteric modulator (PAM), is
undergoing Phase I clinical testing and has potential for treatment of
schizophrenia and anxiety. Under two separate agreements with Merck & Co., Inc.,
we are developing PAMs of mGluR4 and mGluR5 as drugs to treat Parkinson's
disease and schizophrenia, respectively. In addition, SR-One, the corporate
venture arm of GlaxoSmithKline, and Roche Venture Fund have made equity
investments in Addex.

Chris Maggos
Investor Relations & Communications
Addex Pharmaceuticals
+41 22 884 15 11
chris.maggos@addexpharma.com

Disclaimer: The foregoing release contains forward-looking statements that can
be identified by terminology such as "not approvable", "continue", "believes",
"believe", "will", "remained open to exploring", "would", "could", or similar
expressions, or by express or implied discussions regarding Addex
Pharmaceuticals Ltd, its business, the potential approval of its products by
regulatory authorities, or regarding potential future revenues from such
products. Such forward-looking statements reflect the current views of Addex
Pharmaceuticals Ltd regarding future events, and involve known and unknown
risks, uncertainties and other factors that may cause actual results with
allosteric modulators of mGluR4, mGluR2, mGluR5 or other therapeutic targets to
be materially different from any future results, performance or achievements
expressed or implied by such statements. There can be no guarantee that
allosteric modulators of mGluR4, mGluR2 or mGluR5 will be approved for sale in
any market or by any regulatory authority. Nor can there be any guarantee
that allosteric modulators of mGluR4, mGluR2, mGluR5 or other therapeutic
targets will achieve any particular levels of revenue (if any) in the future. In
particular, management's expectations regarding allosteric modulators of
mGluR4, mGluR2, mGluR5 or other therapeutic targets could be affected by, among
other things, unexpected actions by our partners, unexpected regulatory actions
or delays or government regulation generally; unexpected clinical trial results,
including unexpected new clinical data and unexpected additional analysis of
existing clinical data; competition in general; government, industry and general
public pricing pressures; the company's ability to obtain or maintain patent or
other proprietary intellectual property protection. Should one or more of these
risks or uncertainties materialize, or should underlying assumptions prove
incorrect, actual results may vary materially from those anticipated, believed,
estimated or expected. Addex Pharmaceuticals is providing the information in
this press release as of this date and does not undertake any obligation to
update any forward-looking statements contained in this press release as a
result of new information, future events or otherwise.

[HUG#1381443]

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Addex Pharmaceuticals
12, chemin des Aulx Plan-les-Ouates; Geneva Switzerland

ISIN: CH0029850754;

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